Triacylglycerols (triglycerides, TAGs) are the major carbon and energy storage forms in various organisms, and important components of cellular membranes and signaling molecules; they have essential functions in multiple physiological processes and stress regulation. Acyl-CoA: diacylglycerol acyltransferase (DGAT) catalyzes the final and only committed acylation step in the synthesis of TAGs in eukaryotes. The present work identified and isolated a novel gene, UpDGAT1, from the green tide alga Ulva prolifera. The activity of UpDGAT1 was confirmed by heterologous expression in a Saccharomyces cerevisiae TAG-deficient quadruple mutant. Results of thin-layer chromatography and BODIPY staining indicated that UpDGAT1 was able to restore TAG synthesis and lipid body formation in the yeast. Lipid analysis of yeast cells revealed that UpDGAT1 showed broad substrate specificity, accepting saturated as well as mono- and polyunsaturated acyl-CoAs as substrates. High salinity and high temperature stresses increased UpDGAT1 expression and TAG accumulation in U. prolifera. The present study provides clues to the functions of UpDGAT1 in TAG accumulation in, and stress adaptation of, U. prolifera.

甘油三酸酯（甘油三酸酯，TAGs）是各种生物中主要的碳和能量存储形式，是细胞膜和信号分子的重要组成部分。它们在多种生理过程和压力调节中具有基本功能。酰基辅酶A：二酰基甘油酰基转移酶（DGAT）催化真核生物中TAGs合成的最后且唯一的酰化步骤。本工作从绿潮藻Ulva prolifera中鉴定并分离出一个新基因UpDGAT1。UpDGAT1的活性已通过酿酒酵母中的异源表达得到证实TAG缺失的四重突变体。薄层色谱和BODIPY染色的结果表明UpDGAT1能够恢复酵母中的TAG合成和脂质体形成。酵母细胞的脂质分析表明，UpDGAT1具有广泛的底物特异性，可以接受饱和的以及单不饱和和多不饱和的酰基辅酶A作为底物。高盐度和高温应力增加UpDGAT1在表达和TAG积累U.苔。本研究为UpDGAT1在U. prolifera中TAG积累和应激适应中的功能提供了线索。